The present invention relates to automotive vehicles, and more particularly to powertrain control of automotive vehicles.
Various methods can be used in controlling a vehicle powertrain in response to driver requests. In one approach, from an accelerator pedal actuation or brake pedal actuation, a controller determines the acceleration of the vehicle (of positive and/or negative nature, desired by the driver. This acceleration is then used in influencing the wheel drive of the motor vehicle. In lieu of the desired acceleration of the motor vehicle, wheel torque can be used. Such a system is described in U.S. Pat. No. 5,351,776.
The inventors herein have recognized several disadvantages with the above approach. In particular, assuming such an approach is utilized with a brake system in which the brake signal is simply on or off, the driver would have very low resolution in selecting the desired amounts of deceleration or negative wheel torque. Further still, the driver may desire a different amount of deceleration or negative wheel torque after a short brake actuation versus a long brake actuation. The above approach would not take such driver desires into account. Yet another disadvantage with prior approaches recognized by the inventors is that the driver may desire a different mapping between pedal (or brake) actuation and desired acceleration or wheel torque. In particular, if the transmission gear selector is in xe2x80x9cDRIVExe2x80x9d versus xe2x80x9cLOWxe2x80x9d (typically, the selections are PRNDL: park, reverse, drive, neutral, and low), not only may different transmission gears be selected, but also different accelerations or wheel torques may be desired.
Disadvantages of prior approaches are overcome by a method for controlling a powertrain of a vehicle. The method comprises detecting operation of a first driver actuated element, detecting operation of a second driver actuated element, detecting operation of a third driver actuated element, and determining a desired vehicle condition based on said detected first, second, and third driver actuated element. The first element can be pedal position. The second element can be a brake actuator or, more specifically, brake actuation duration. The third element can be a gear selection lever.
By including brake duration, it is possible to provide the driver improved resolution depending on how long the brake actuator is depressed. Further, it is possible to provide more tailored drive feel by providing different vehicle operation depending on the position of the gear selection lever.
Advantages of the present invention can include improved vehicle performance and operation.
It is important to note that the first, second, and third elements can be other elements than those noted above. For example, they can be a cruise control actuator, a turn signal actuator, or a clutch actuator. Further, the determined vehicle condition can be a desired vehicle acceleration, a desired powertrain output torque, or a desired transmission gear ratio.